Turbomachines (such as aircraft engines and stationary gas turbines) have a rotor that includes a plurality of rotor blades, as well as at least one axially adjacent guide vane row. The guide vanes are used for optimizing the flow conditions for the rotor blades; the guide vanes and the rotor blades are serially disposed in the primary flow direction. Along the lines of the present invention, the term “guide vane” or “guide vane segment” is to be broadly understood, in particular in the sense of a “stator ring.” Thus, this term also encompasses flow-deflecting profiles which, as constituent parts of what is generally referred to as a turbine exit case, are disposed axially downstream of the last rotor blade row of a low-pressure turbine, as well as flow-deflecting profiles, which, as constituent parts of a turbine intermediate case, are disposed between two turbine regions, such as the low-pressure turbine and the high-pressure turbine, for example.
A guide vane row may include a radially inner and a radially outer shroud, as well as a plurality of guide vane airfoils disposed therebetween; in this text, the designations “radial,” “axial,” and “circumferential” always relate—unless indicated otherwise—to the axis of rotation of an (existing or intended) rotor shaft that is surrounded by the guide vane row. The axis of rotation generally corresponds to what is commonly known as the machine axis of the turbomachine. The guide vane row can be composed of a plurality of guide vane segments, which can each include a radially inner and/or a radially outer shroud plate, as well as a guide vane airfoil or a plurality of guide vane airfoils. Together, the radially inner shroud plates thereby form the inner shroud, and the radially outer shroud plates, the outer shroud; in each case, the shrouds are preferably configured as a closed ring which forms a radial delimitation for the main gas flow.
Analogously, in a radially inner region, the rotor blades can have a base plate that is adapted to be secured to a rotor shaft via a blade root that is insertable or inserted into a rotor disk, for example. A base plate of this kind preferably has an axial projection that, together with a shroud of a guide vane row facing the projection, is adapted for diminishing any radial leakage flow.
Turbomachines having such guide vane assemblies and rotor blade assemblies have been continually improved over the course of time. The publications, German Patent Application DE 10 2008 011 746 A1, U.S. Patent Application 2007/0243061 A1 and European Patent Application EP 2 236 748 A1, describe options for reducing disadvantageous leakage flows, for example.